This invention relates to a processing device for stirring or reducing foods, particularly a handheld blender, according to the prior-art portion of claim 1.
Processing devices are known from WO 96/10944 (PCT/EP95/03932) or EP-A1 0 724 857, for example. Such processing devices or handheld blenders are used in great diversity, particularly during the daily preparation of foods, in order to reduce and blend food materials, for example. Such handheld blenders typically have a motor housing adjoining an elongated housing part whose end becomes a shield open at its bottom end and also referred to as the housing bell. Inside the motor housing is a drive motor which drives a tool shaft extending through the elongated housing part and usually having a cutter blade fitted to its end in the area of the shield. The shield is designed big enough to completely encompass the cutter blade and to project a defined distance beyond the end of the shaft or cutter blade as seen looking in the direction of the tool shaft's axis. One of the functions performed by the shield is to protect the user of the device from the rotating cutter blade. Another is to act as a splash guard, particularly when processing low-viscosity foods.
Such processing devices or handheld blenders can be adapted to different requirements by selection of the speed at which the shaft and hence the cutter blade rotates. Problems may arise when wishing to reduce solid foods such as carrots. In this case the carrots must first be cut into short enough pieces to be able to enter the inside of the bell in order to reach the bite of the cutter blade when the handheld blender or its housing bell is immersed in the pre-cut carrots. If these carrot pieces are too big or the container holding the carrots is too small to allow relative movement of the carrot pieces at all or only with difficulty, it can happen that the edge of the shield comes to rest on such large pieces, preventing it from advancing any further. Consequently, the cutter blade fails to reach the carrot pieces in order to reduce them. This problem can usually be remedied by raising the handheld blender and immersing it again into the food pieces to be reduced until it engages the pieces.
From DE-B-12 24 007 there is known a processing device having a processing tool designed to be pushed in and out of the bell compartment accommodating the processing tool in order to be better able to clean the bell compartment and the processing tool.
Similarly, from EP 0 078 050 there is known a processing device such as a handheld blender on which the processing tool can be moved out of the bell against the force of a spring only when the bell is immersed in liquid foods. Moving the processing tool out of the bell should enable the foods to be homogeneously and completely mixed and reduced at high speed. As soon as the bell is removed from the foods, the processing tool retracts into the interior of the bell compartment with an axial sliding movement caused by the spring force. Injuries are thus prevented because the processing tool is now protected by the bell.
From DE-A-19504638 and U.S. Pat. No. 3,299,924, processing devices of the type initially referred to are known providing for relative displacement of the bell edge and the work performing element. The embodiments of the adjusting devices are mechanically complex and therefore expensive.
It is an object of the present invention to improve upon a processing device, particularly a handheld blender, in such a way that the processing tool, in particular a cutter blade, is not only sufficiently protected in an initial position by the shield but also well suited to better reduce large pieces of solid foods.